The present invention relates to semiconductor manufacturing facilities, semiconductor manufacturing apparatuses and a semiconductor manufacturing method and, more particularly, to a semiconductor manufacturing facility which recover heat emitted from semiconductor manufacturing equipment installed in a clean room and a semiconductor manufacturing apparatus used in such a semiconductor manufacturing facility and a semiconductor manufacturing method performed by such a semiconductor manufacturing facility.
Some semiconductor manufacturing equipments are provided with a heat source. For example, a heating furnace is provided in a vertical heat treatment apparatus, which performs a heat treatment on semiconductor wafers supported by a support tool in a shelf-like arrangement. The outer surface of such a heating furnace reaches a high temperature of about several hundred degrees, and if the heating furnace is laid in a bare state, a heat is emitted from the heating furnace to the surrounding area, which may exert a bad influence on apparatuses in the surrounding area. Additionally, in a case in which an operator touches the heating furnace by mistake, the operator may receive a burn.
Accordingly, it is necessary to cool the outer surface of the heating furnace, which is a heat source. FIG. 1A is a perspective view of a coil-type cooling pipe 10, which is conventionally used to cool a heating furnace, which is a heat source, and FIG. 1B is a front view of the coil-type cooling pipe 10. The cooling pipe 10 is wound on the periphery of the heating furnace, and cooling water is supplied to a lower cooling water inlet port 11 and the cooling water flows out through an upper cooling water outlet port 12. Release of heat to outside (inside the clean room) is suppressed by the cooling water absorbing the heat of the heat source.
The temperature of the cooling water supplied to the cooling water inlet port 11 is maintained at about 23xc2x0 C., which is a setting temperature of a clean room so that dew formation does not occur. The temperature of the cooling water exiting from the cooling water outlet port 12 normally ranges from about 25xc2x0 C. to 28xc2x0 C. although the temperature varies according to the operating conditions. That is, a temperature difference between the inlet port 11 and the outlet port 12 is about 5xc2x0 C. The reason for this is because if the temperature difference is large, the temperature difference influences the temperature distribution in the heat treatment atmosphere in the heating furnace, which lowers the process performance. Additionally, apparatus deterioration may be festinated in hardware. Further, it is undesired that a large temperature distribution is created in the clean room.
FIG. 2 is a structural diagram showing a supply and cooling system of the cooling water supplied to the coil-type cooling pipe 10. Cold water of about 6xc2x0 C., which is cooled by a refrigerating machine 101 and stored in a cold-water tank 102, is delivered to a heat exchanger 103 so as to cool the cooling water for the coil-type cooling pipe 10, and the cold water is returned to the cold-water tank 102. On the other hand, the cooling water stored in a buffer tank 104, which has a temperature higher than 23xc2x0 C., is delivered to the heat exchanger 103 by a water pump 105, and is cooled to the temperature of 23xc2x0 C. by heat exchange with the cold water of 6xc2x0 C. The cooling water enters the inlet port 11, passes through the cooling pipe 10 and exits from the outlet port 12 so as to be returned to the buffer tank 104. It should be noted that, in FIG. 2, 106 indicates a cooling tower, 107 indicates a temperature sensor, and 108-110 indicate water pumps.
In the above-mentioned cooling apparatus, the temperature of the cooling water supplied to the coil-type cooling pipe 10 must be set to the setting temperature of 23xc2x0 C. of the clean room. Accordingly, the cooling water of the separate system must be controlled to about 23xc2x0 C. by heat exchange by the heat exchanger 103 using the cold water of about 6xc2x0 C. produced by the refrigerating machine 101. Accordingly, the refrigerating machine 101 and the heat exchanger 103 are needed, thereby increasing a thermal energy loss. Additionally, since there are two cooling water delivery lines, a water pump must be provided to each of the lines. As a result, there is a problem in that an area occupied by the facility is increased, and a facility equipment cost is increased.
In the above-mentioned cooling system, an amount Q of heat absorbed by the cooling water from the heat source is represented by the following equation (1), where amount of cooling water is W, specific heat is Cw, inlet temperature is Ti, outlet temperature is T0 and temperature difference between inlet and outlet is xcex94T.
Q=Wxc2x7Cwxc2x7(T0xe2x88x92Ti)=Wxc2x7Cwxc2x7xcex94Txe2x80x83xe2x80x83(1)
In the equation (1), since the specific heat Cw is constant, the amount W of cooling water must be increased so as to decrease the temperature difference xcex94T to about 5xc2x0 C. Accordingly, a large amount of cooling water is needed, and there is a problem in that a power cost of the pump is increased. Additionally, a micro vibration is generated due to an inevitable increase in the amount of cooling water flowing through a main water delivery pipe due to a large amount of cooling water flowing through the cooling pipe. The generated micro vibration propagates the building frame (structure) of the clean room, and consequently propagates an area in which an exposure machine and a scanning electron microscope which are sensitive to a vibration are installed, which exerts a bad influence on those equipment.
Further, since a constant amount of cooling water is supplied to the inlet port 11 of the cooing water coil 10, a large heat load is applied to the semiconductor manufacturing apparatus. The temperature of the outlet port 12 is increased when the temperature of the heat source is increased, and, on the contrary, an unnecessary cooing is made when the heat load is small. Accordingly, the heat load, which is used for the power to the water pump and producing unnecessary cooling water, is consumed, thereby increasing a loss of energy that is not efficiently used.
In addition to the above-mentioned problems, rust or corrosion occurs in the cooling pipe, the piping, the pump and the heat exchanger through which the cooling water flows, and it is one of the issues to prevent the rust or corrosion.
It is an object of the present invention to provide an improved and useful semiconductor manufacturing facility in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide a semiconductor manufacturing facility and a semiconductor manufacturing apparatus having a cooling apparatus which has a small scale and is capable of reducing an amount of cooling water.
In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention a semiconductor manufacturing facility provided with semiconductor manufacturing equipment which generates heat during operation and a cooling apparatus for cooling a heat generating part of the semiconductor manufacturing equipment,
the cooling apparatus comprising:
an inner fluid passage formed so as to surround a periphery of the heat generating part and having an inlet port of cooling water on a vertically lower portion thereof;
an outer fluid passage communicated with the inner fluid passage and having an outlet port of the cooling water on a vertically upper portion thereof, the outer fluid passage being formed so as to surround a periphery of the inner fluid passage and is capable of exchanging heat with the cooling water in the inner fluid passage;
a communication passage connecting a vertically upper portion of the inner fluid passage and a vertically lower portion of the outer fluid passage; and
a cooling water supply facility which cools the cooling water flowing out of the outlet port of the outer fluid passage and supplies the cooling water to the inlet port of the inner fluid passage.
Additionally, there is provided according to another aspect of the present invention a semiconductor manufacturing facility provided with semiconductor manufacturing equipment generating heat during operation and a cooling apparatus for cooling a heat generating part of the semiconductor manufacturing equipment,
the cooling apparatus comprising:
an inner fluid passage formed so as to surround a periphery of the heat generating part and having an inlet port of cooling water on a vertically lower portion thereof;
an outer fluid passage communicated with the inner fluid passage and having an outlet port of the cooling water on a vertically lower portion thereof, the outer fluid passage being formed so as to surround a periphery of the inner fluid passage and is capable of exchanging heat with the cooling water in the inner fluid passage;
a communication passage connecting a vertically upper portion of the inner fluid passage and a vertically upper portion of the outer fluid passage; and
a cooling water supply facility which cools the cooling water flowing out of the outlet port of the outer fluid passage and supplies the cooling water to the inlet port of the inner fluid passage.
As a specific operational example, an amount of flow of the cooling water is controlled so that a temperature of the cooling water at the inlet port of the inner fluid passage is set to a temperature lower than a temperature of air surrounding the semiconductor manufacturing equipment, and a temperature of the cooling water at the outlet port of the outer fluid passage is set to be equal to a temperature of an environmental in which the semiconductor manufacturing equipment is placed.
According to the present invention, there is no possibility of dew formation even if the temperature of the cooling water at the inlet port is set to a temperature considerably lower than the temperature of the environment in which the semiconductor manufacturing equipment is placed since the inner fluid passage is located between the outer fluid passage and the heat generating part. Additionally, if the temperature difference between the cooling water at the inlet port and the cooling water at the outlet port is large, the temperature difference is shared by the inner fluid passage and the outer fluid passage, resulting in not so large temperature difference between one end and the other end of the inner fluid passage which surrounds the heat generating part. Accordingly, since the temperature difference between the temperature of the cooling water to be supplied and the temperature of the cooling water to be exhausted can be large, the cooling facility can be simplified by reducing the cooling area and an amount of the cooling water can be decreased. Further, a micro vibration of the pipe system and the inner fluid passage and the outer fluid passage can be suppressed, the process of the semiconductor manufacturing equipment is prevented from having a bad influenced.
In the present invention, the cooling water supply facility may include a refrigerating machine, and cold water produced by the refrigerating machine may be used as the cooling water supplied to the inlet port of the inner fluid passage. Additionally, the cooling water supply facility may include a refrigerating machine and a heat exchanger, and the cooling water supplied to the inlet port of the inner fluid passage may be cooled by the heat exchanger, which exchanges heat with cold water produced by said refrigerating machine.
Further, in the present invention the cooling water supply facility may comprise: a flow control part controlling an amount of flow of the cooling water supplied to the inlet port of the inner fluid passage; a temperature detecting part detecting a temperature of the cooling water at the outlet port of the outer fluid passage; and a control part controlling an amount of delivery of the cooling water via the flow control part based on a temperature detection value detected by the temperature detecting part so that the temperature of the cooling water of the outlet port of the outer fluid passage becomes a setting temperature. Alternatively, the cooling water supply facility may comprise: a bypass fluid passage connecting between the inlet port of the inner fluid passage and the outlet port of the outer fluid passage; a flow control part provided to the bypass fluid passage; a temperature detecting part detecting a temperature of the cooling water at the outlet port of the outer fluid passage; and a control part controlling an amount of delivery of the cooling water via the flow control part based on a temperature detection value detected by the temperature detecting part so that the temperature of the cooling water of the outlet port of said outer fluid passage becomes a setting temperature.
In the present invention, it is preferred to b a structure provided with deoxidizing means for removing dissolved oxygen in the cooling water supplied to the inlet port of the inner fluid passage; and reducing agent dissolving means for dissolving reducing agent in the cooling water. According to this, a metal constituting the fluid passage through which the cooling water passes is no oxidized, and formation of pinholes due to corrosion can be prevented since the cooling water has a reducing action. In this case, for example, the deoxidizing means and the reducing agent dissolving means may be means for supplying a mixture gas of a deoxidizing gas and a reducing gas into the cooling water by bubbling. Additionally, the cooling water may be stored in a hermetically sealed tank, and the deoxidizing means may be depressurizing means for depressurizing a gas phase part in the tank and the reducing agent dissolving means may supply a reducing gas to the depressurized gas phase part. The reducing agent may be hydrogen, and the hydrogen may be dissolved in the cooling water supplied to the inlet port of the inner fluid passage, a concentration of the hydrogen is preferably equal to or greater than 0.4 ppm and equal to or less than a saturated solubility. Additionally, it is preferred that a heat insulator be provided on an outer surface of a fluid passage part through which the cooling water flows, the heat insulator material being made of a material which does not generate a gaseous contaminant.
It should be noted that there is provided according to another aspect of the present invention a semiconductor manufacturing apparatus provided with the above-mentioned cooling apparatus. Additionally, there is provided according to yet another aspect of the present invention a semiconductor manufacturing method performed in the above-mentioned semiconductor manufacturing facility provided with the cooling apparatus.